Transfusion device and liquid supply tube

ABSTRACT

The structural complexity of conventional transfusing devices is eliminated, and it is made possible to supply a minute amount of liquid medicine with high accuracy with a simple structure, whereby a portable transfusion pump is realized. A cylindrical rotary drive member ( 24 ) equipped with a rotation shaft ( 23 ) is arranged opposite to a support plate ( 22 ), and a liquid supply tube ( 16 ) is arranged between the support plate ( 22 ) and the rotary drive member ( 24 ). On the outer peripheral surface of the rotary drive member ( 24 ), a pressing protrusion ( 24   a ) extending spirally around the axis is formed integrally. A flexible sheet ( 25 ) is provided between the rotary drive member ( 24 ) and the liquid supply tube ( 16 ). The upper and lower ends of this sheet ( 25 ) are directly or indirectly fixed to a base ( 10 ) and the support plate ( 22 ).

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a transfusing device and a liquidsupply tube and, in particular, to a structure suitable for atransfusing device for injecting a liquid medicine into the body of apatient and to a structure suitable for a liquid supply tube, which is aconstituent part of a transfusing device.

2. Background Art

In a hospital or the like, a liquid medicine is injected into the bodyof a patient usually by drip transfusion, in which a plastic transfusingtube is connected to a liquid medicine sack, which is suspended fromabove, and a needle is attached to the forward end of the transfusingtube and inserted into a blood vessel of the patient or the like. Toaccurately control the amount of liquid medicine or to enhance thesafety of the operation, various types of transfusing device constructedso as to be capable of forcibly sending the liquid medicine into thebody of the patient may be adopted.

In one type of such transfusing device, a peristaltic transfusing pumpmay be employed in which the liquid medicine in a flexible liquid supplytube is conveyed by squeezing the liquid supply tube. Two types ofperistaltic transfusing pump are employed: one is a rotary typetransfusing pump in which a flexible liquid supply tube is bent into asemi-circular shape and in which the bent portion of the liquid supplytube is squeezed from inside to conveyed liquid medicine by a rollermounted to the forward end of a rotatable arm provided on the inner sideof the bent portion of the liquid supply tube; and the other is a fingertype transfusing pump in which a plurality of fingers (pressurizingmembers) are sequentially pressed against the outer surface of theliquid supply tube in the direction in which the liquid medicine in theliquid supply tube is to be conveyed to thereby convey the liquidmedicine.

The rotary type transfusing pump is advantageous in that it has arelatively simple structure. However, it is relatively difficult toaccurately control the minute amount of liquid medicine to be conveyed.Further, it does not easily allow the size of the conveying section tobe reduced.

A typical example of the finger type transfusing pump is disclosed inJapanese Patent Publication No. 61-55393. In the transfusing pump of theabove example, a finger is engaged with each of a plurality of camplates mounted to a rotation shaft, and the fingers are caused to movetoward and away from the liquid supply tube by rotating operation of thecam plates when the rotation shaft rotates. This peristaltic transfusingpump using fingers is advantageous in that the injection pressure forthe liquid medicine can be made high and that the minute amount ofliquid medicine can be controlled with high accuracy. However, since itis necessary to drive a large number of fingers with high accuracy, thestructure of the pump is rather complicated, making it difficult toreduce the production cost. Further, it is difficult to achieve areduction in size.

A balloon type transfusing device provides a function equivalent to thatof the above transfusing device. In the balloon type transfusing device,liquid medicine is put in the balloon, which is formed of syntheticrubber or the like, in advance, and the liquid medicine is pushedforward by contraction force of the balloon. This transfusing device isadvantageous in that it has a very simple structure and can be producedat low cost. However, in a transfusing device using a balloon, thedischarge pressure of the liquid medicine varies depending upon theamount of liquid medicine left in the balloon, so that the speed atwhich the liquid medicine is supplied also varies. More specifically,the discharge pressure is gradually reduced from the initial pressure asthe transfusion time elapses, and the amount of liquid medicine suppliedalso diminishes gradually. In this way, the supply pressure for theliquid medicine and its amount supplied vary. Further, it is difficultto control the speed at which the liquid medicine is supplied.

In performing medical treatment, it is sometimes necessary to give aminute amount of liquid medicine over a long period of time to mitigatethe strain on the patient. To make it possible to give liquid medicineover a long period of time, development of a portable transfusing deviceis to be expected. To realize a portable transfusing device, a reductionin the size and weight of the device is indispensable. Conventionally,there has been proposed no transfusing device structure which is smalland light enough to provide a satisfactory portability. Further, it isnot yet technically possible to administer a minute amount of liquidmedicine into the body of the patient with high accuracy.

DISCLOSURE OF INVENTION

In a first aspect of the present invention, there is provided atransfusing device comprising a flexible liquid supply tube, a supportmember supporting the liquid supply tube from one side, and a rotarydrive member which is adjacent to the liquid supply tube on the oppositeside of the support member and which is equipped with a rotation shaftsubstantially parallel with the direction in which the liquid supplytube extends, wherein one or a plurality of pressing protrusions forpressurizing the liquid supply tube are integrally provided on the outerperipheral surface of the rotary drive member, and wherein the pressingprotrusions are spirally formed or spirally arranged on the outerperipheral surface of the rotary drive member.

In a second aspect of the present invention, there is provided atransfusing device comprising a flexible liquid supply tube, a supportmember supporting the liquid supply tube from one side, and a pluralityof fingers which are adjacent to the liquid supply tube on the oppositeside of the support member and which are arranged substantially parallelwith the direction in which the liquid supply tube extends, wherein thefingers act on the liquid supply tube to pressurize the liquid supplytube, wherein there is provided a heat transfer means for heating orcooling the fingers or a drive member for driving the fingers, andwherein the fingers or the drive member is formed of a heat deformationmaterial which deforms so as to pressurize the liquid supply tube by theheat transfer of the heat transfer means.

In a third aspect of the present invention, there is provided a liquidsupply tube which deforms by external stress due to at least partialflexibility and which conveys liquid medicine therein by thisdeformation, wherein there are provided a pair of component members atleast one of which is equipped with a plate like portion formed of anelastic material or a flexible material, and wherein the two sides withrespect to the width direction of the component members are joinedtogether to form joint portions, the gap defined between the jointportions being formed as a liquid passage.

In a fourth aspect of the present invention, there is provided atransfusing device comprising liquid pressurizing means for pressurizingliquid medicine, a flexible liquid supply tube connected to the liquidpressurizing means, a support member supporting the liquid supply tubefrom one side, a first finger which is adjacent to the liquid supplytube on the opposite side of the support member, which is arrangedsubstantially parallel with the direction in which the liquid supplytube extends and which is arranged at the upstream end, a second fingerarranged at the downstream end, and a plurality of third fingersarranged between the first finger and the second finger, the liquidsupply tube being capable of causing the first, second and third fingersto act on the liquid supply tube to pressurize them, wherein the liquidmedicine is discharged by sequentially repeating the following steps: astep for pressurizing the liquid supply tube by the first finger withthe second finger pressurizing the liquid supply tube, a step forcanceling the pressurization by the second finger and pressurizing theliquid supply tube by the third fingers, and a step for pressurizing theliquid supply tube by the second finger to cancel the pressurization bythe first finger and canceling the pressurization by the third fingers.

In a fifth aspect of the present invention, there is provided atransfusing device comprising liquid pressurizing means for pressurizingliquid medicine, a transfusion route for conveying the pressurizedliquid medicine, and a transfusion pump provided in the transfusionroute, wherein the transfusion pump is equipped with an inlet valveprovided at the inlet of the pump, a pump chamber formed on the innerside of the introducing valve, a discharge valve provided at the outletof the pump, and a discharge mechanism for discharging the liquidmedicine by varying the volume of the pump chamber, and wherein theliquid medicine is discharged by sequentially repeating the followingsteps: a step for closing the inlet valve with the discharge valve beingclosed, a step for opening the discharge valve and effecting a reductionin the volume of the pump chamber by the discharge mechanism, and a stepfor closing the discharge valve and opening the inlet vale to restorethe volume of the pump chamber.

In all of the above aspects of the invention, a reduction in the sizeand weight of the device can be achieved as compared with theconventional transfusing devices by reducing the number of parts,simplifying the structure of the device, etc. Further, in all of them,it is possible to supply a minute amount of liquid medicine with highaccuracy.

In the above aspects of the invention, the liquid supply tube is aflexible tube which is deformed in order to send out the liquid medicinetherein in the direction in which the tube extends. It is formed, forexample, by synthetic resin and arranged in the transfusing device. Thetransfusing tube as described in the present specification is a tube forsupplying the liquid medicine conveyed from the transfusing device tothe patient. Usually, it is equivalent to what is connected to theliquid medicine sack used in transfusion. Although it is desirable forthe liquid supply tube to be formed of a special material which hasenough durability to withstand repeated deformation, it may also beformed of a material similar to that of the transfusing tube.Alternatively, a part of the transfusing tube may be used as the liquidsupply tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view partly in section showing an essential part of afirst embodiment in the first aspect of the present invention;

FIG. 2 is a cross-sectional view showing the essential part of the firstembodiment in the first aspect of the present invention;

FIG. 3 is a front view partly in section showing the essential part ofthe first embodiment in the first aspect of the present invention in adifferent state;

FIG. 4 is a front view partly in section showing an essential part of asecond embodiment in the first aspect of the present invention;

FIG. 5 is a plan view of a rotary drive member of the second embodimentin the first aspect of the present invention;

FIG. 6 is a cross-sectional view showing an essential part of a thirdembodiment in the first aspect of the present invention;

FIG. 7 is a cross-sectional view showing an essential part of a fourthembodiment in the first aspect of the present invention;

FIG. 8 is a plan view showing the configuration of an insertion plate ofthe fourth embodiment in the first aspect of the present invention;

FIG. 9 is a front view showing the inner structure of a first embodimentin the second aspect of the present invention;

FIG. 10 is a left-hand side front view showing the inner structure ofthe first embodiment in the second aspect of the present invention;

FIG. 11 is an enlarged sectional view showing the sectionalconfiguration of a heat generating portion of a thermal array of thefirst embodiment in the second aspect of the present invention;

FIG. 12 is a schematic perspective view showing an essential part of asecond embodiment in the second aspect of the present invention;

FIG. 13 is a schematic longitudinal sectional view showing an essentialpart of a third embodiment in the second aspect of the presentinvention;

FIG. 14 is a schematic longitudinal sectional view showing an essentialpart of a fourth embodiment in the second aspect of the presentinvention;

FIG. 15 is a schematic longitudinal sectional view taken along a planeorthogonal to the section of FIG. 14, showing the essential part of thefourth embodiment in the second aspect of the present invention;

FIG. 16 is a schematic enlarged plan view showing the structure andarrangement of fingers of the fourth embodiment in the second aspect ofthe present invention;

FIG. 17 is a partial perspective view schematically showing thestructure of a liquid supply tube of a first embodiment in the thirdaspect of the present invention;

FIG. 18 is a longitudinal sectional view showing the sectional structureof the first embodiment in the third aspect of the present invention;

FIG. 19 is a longitudinal sectional view showing a modification of thefirst embodiment in the third aspect of the present invention;

FIG. 20 is a partial perspective view schematically showing thestructure of a liquid supply tube of a second embodiment in the thirdaspect of the present invention;

FIG. 21 is a longitudinal sectional view showing the sectional structureof the second embodiment in the third aspect of the present invention;

FIG. 22 is a longitudinal sectional view showing a modification of thesecond embodiment in the third aspect of the present invention;

FIG. 23 is a schematic perspective view showing the structure of atransfusing pump according to the second embodiment in the third aspectof the present invention;

FIG. 24 is a longitudinal sectional view showing the sectionalconfiguration of a transfusing pump according to the second embodimentin the third aspect of the present invention;

FIG. 25 is a longitudinal sectional view showing a modification of thetransfusing pump according to the second embodiment in the third aspectof the present invention;

FIG. 26 is a schematic perspective view showing the structure of a thirdembodiment in the third aspect of the present invention;

FIG. 27 is a schematic perspective view showing the configuration of aconnection connector for connecting the first or the second embodimentin the third aspect of the present invention to the transfusing tube;

FIG. 28 is a schematic diagram showing the structure of an embodiment inthe fourth aspect of the present invention;

FIG. 29 is a liquid medicine pressurizing structure according to anembodiment in the fourth aspect of the present invention;

FIGS. 30 through 33 are schematic diagrams showing how a transfusingpump according to an embodiment in the fourth aspect of the inventionoperates;

FIG. 34 is a schematic diagram showing the structure of an embodiment inthe fifth aspect of the present invention;

FIGS. 35 through 38 are schematic diagrams showing how a transfusingpump according to an embodiment in the fifth aspect of the inventionoperates;

FIG. 39 is a schematic diagram showing the general construction of atransfusing device that can be commonly used in the embodiments in thefirst, second, fourth and fifth aspects of the present invention; and

FIG. 40 is a schematic front view showing the appearance of atransfusing device that can be commonly used in the embodiments in thefirst, second, fourth and fifth aspects of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

To describe the present invention more specifically, a plurality ofpreferable embodiments will be described with reference to theaccompanying drawings.

EMBODIMENTS IN THE FIRST ASPECT OF THE INVENTION

In the first aspect of the present invention, there is provided apressing protrusion spirally formed on the outer peripheral surface of arotary drive member or a plurality of spirally arranged pressingprotrusions; by rotating the rotary drive member, that portion of theliquid supply tube pressed by the pressing protrusion is moved tothereby convey the liquid medicine.

First Embodiment

FIG. 1 is a front view showing the essential part of a transfusingdevice according to the first embodiment of the present invention, andFIG. 2 is a cross-sectional view showing the essential part of thetransfusing device of the first embodiment. In this transfusing device,a support plate 22 is mounted on a base 10 through the intermediation ofsprings 11. At a position opposite to this support plate 22, acylindrical rotary drive member 24 equipped with a rotation shaft 23 isrotatably arranged. While this rotation shaft 23 is formed integrallywith the rotary drive member 24, it is possible, in a modification, forthe rotation shaft 23 and the rotary drive member 24 to be formed asseparate members and firmly attached to each other by adhesion, weldingor the like. A liquid supply tube 16 is arranged between the supportplate 22 and the rotary drive member 24. The axis of the rotation shaft23 and the rotary drive member 24 is parallel with the direction inwhich the liquid supply tube 16 extends (i.e., vertically as seen in thedrawing).

On the outer peripheral surface of the rotary drive member 24, apressing protrusion 24 a extending spirally around the axis thereof isformed integrally. This pressing protrusion 24 a pressurizes the liquidsupply tube 16 through the intermediation of a sheet 25 described belowand depresses the flexible liquid supply tube 16. When the rotationshaft 23 is rotated by a drive motor (not shown) or the like, thepressing protrusion 24 a on the outer peripheral surface of the rotarydrive member 24 also rotates. As a result, that portion of the liquidsupply tube 16 which is depressed by the pressing protrusion 24 a isgradually displaced downwards.

A cylindrical flexible sheet 25 is fitted onto the rotary drive member24 and exists between the liquid supply tube 16 and the rotary drivemember 24. The upper and lower ends of this sheet 25 is fasteneddirectly or indirectly to the base 10 and the support plate 22. Thesheet 25 serves to restrain the generation of twisting, etc. of theliquid supply tube 16 when it receives frictional stress in the rotatingdirection as a result of the pressing protrusion 24 a of the rotarydrive member 24 coming into direct contact with the liquid supply tube16. It is desirable that at least the surface of that side which comesinto contact with the rotary drive member 24 offer low friction.

In order that no stress in an undesirable direction may be generated inthe liquid supply tube 16 as stated above, it is most desirable for thesheet 25 to be directly or indirectly fastened to the base 10 and thesupport plate 22. Conversely, it may be directly or indirectly fastenedto the rotation shaft 23 and the rotary drive member 24. In this case,it is desirable for the surface of that side of the sheet 25 which comesinto contact with the liquid supply tube 16 of the sheet 25 to have lowfriction. To mitigate the frictional force on the surface of the sheet,it is possible to form the sheet of a material offering little friction,or provide a low friction coating on the surface of the sheet.

As shown in FIG. 2, the support plate 22 has an opposing surface 22 awhich has an arcuate sectional configuration such that it wraps up therotary drive member 24 from the right-hand side as seen in the drawing.The liquid supply tube 16 is held between this opposing surface 22 a andthe sheet 25 surrounding the surface of the rotary drive member 24.

When the rotary drive member 24 rotates, the spiral pressing protrusion24 a formed on the outer peripheral surface thereof also rotates, andthat portion of the pressing protrusion 24 a which depresses the liquidsupply tube 16 is gradually displaced downwards. When this depressingportion has moved to the lower end of the support plate 22, the pressingprotrusion 24 a starts to depress the liquid supply tube 16 in thevicinity of the upper end of the support plate 22, as shown in FIG. 3,and this depressing portion moves again downwards from the upper end ofthe support plate 22. This downward displacement (peristaltic motion) ofthe depressing portion is repeated, and the liquid medicine in theliquid supply tube 16 continues to be conveyed downwards as seen in thedrawing.

In this embodiment, the vertical length of the support plate 22 and thepitch of the pressing protrusion 24 a are substantially the same, andthere is always a depressed portion which is being depressed by thepressing protrusion 24 a within the area in which the liquid supply tube16 is in contact with the support plate 16. The pitch of the spiralpressing protrusion 24 a is not larger than the vertical length of thesupport plate 22, and within a range not less than the least diameterthat allows deformation corresponding to the flexibility of the liquidsupply tube 16 and the sheet 25. It is possible to make the spiral pitchof the pressing protrusion 24 a smaller so that the liquid supply tube16 may be depressed at a plurality of positions. If the spiral pitch ofthe pressing protrusion 22 is larger than the vertical length of thesupport plate 22, it is possible to convey the liquid medicine althoughin that case there is a possibility of an uncontrolled flow of liquidmedicine being generated. There is practically no problem if the spiralpitch is slightly larger than the length of the support plate 22. When,conversely, the pitch is less than the least diameter that allowsdeformation of the liquid supply tube 16 and the sheet 25, the pumpcapacity of the transfusion pump is lost, or the pumping efficiencythereof deteriorates.

In this embodiment, pumping operation is possible solely by attachingthe rotary drive member 24 to the rotation shaft 23 and rotating them.Thus, there is no need to provide as in the case of the conventionalfinger type transfusion pump to provide an assembly formed by a largenumber of cam plates and depression fingers, so that it is possible toachieve a reliable liquid supply function with a very simple structure.Thus, due to the simple structure, a reduction in size is possible, andthe number of parts is reduced. At the same time, a reduction in cost isachieved due to the improvement in assembly. Further, since failureoccurs less often, an improvement is achieved in terms of safety andmaintenance.

In particular, in this embodiment, a spiral pressing protrusion isprovided on the outer peripheral surface of the rotary drive member,whereby, unlike the case of the conventional finger type transfusionpump, it is possible to squeeze the liquid supply tube endlessly andcontinuously (move the depressing portion in the direction in which itextends), so that it is possible to eliminate vibration of the supportplate 12 pressurized by the springs 11, convey the liquid medicineefficiently, and improve the pumping efficiency. Further, it is possibleto restrain pulsation of the liquid medicine.

In this embodiment, it is also possible to simultaneously adopt variousimproved systems of the conventional finger type transfusion pumps. Forexample, to reduce the supply pressure of the liquid medicine due to theoperating period of the transfusion pump or pulsation of the supplyspeed, it is possible to arrange depression fingers which come in andout so as to vary the liquid passage sectional area of the liquid supplytube 16 in synchronism with the pulsation period of the liquid medicine.These fingers operate so as to compensate for the pulsation of theliquid medicine, so that it is possible to mitigate the pulsation andcreate a constant liquid medicine flow. Further, to provide a functionby which stopping of the liquid medicine in the liquid supply tube isdetected to give alarm, it is possible to provide a mechanism fordetecting the difference between the inner pressure on the upstream sideand the inner pressure on the downstream side, that is, difference inpressure between the inlet and outlet of the pump.

Second Embodiment

Next, a second embodiment of the present invention will be describedwith reference to FIGS. 4 and 5. Like the first embodiment, thisembodiment is equipped with the base 10, the springs 11, the supportplate 22, the rotation shaft 23 and the sheet 25. It differs from thefirst embodiment in that a rotary drive member 34 is provided instead ofthe rotary drive member 24. This rotary drive member 34 is fastened tothe rotation shaft 23 and equipped with a plurality of disc-like drivesections 34 a which are decentered with respect to the rotation axis. Asshown in FIG. 5, this rotary drive member 34 consists of a plurality ofdrive sections 34 a of the same configuration which are sequentiallydeviated from each other by 45 degrees around the axis of the rotationshaft 23.

This rotary drive member may be cut from a solid shaft material by amachine tool capable of micro three-dimensional machining.Alternatively, each drive section 34 a may be formed by cutting,stamping, forging, etc., and then the drive sections 34 a may be formedinto an integral unit in which the phase difference θ between adjacentdrive sections 34 a (See FIG. 5) is 45 degrees by adhesion, crimping,welding, etc. Further, it is not necessary for the drive sections 34 ato be directly fastened to each other. They may be indirectly formedinto an integral unit by being individually fastened to the rotationshaft 23.

In this embodiment, each decentered drive section 34 a may have acircular plan configuration. Alternatively, it may be a deformedcircular configuration. Further, instead of being decentered, all thedrive sections may be arranged concentrically. In this case, protrusionsprotruding simply from the outer peripheral surface are provided, andthe angular positions of the protrusions are deviated from each other.In any case, in each drive section 34 a, a pressing protrusion 34 b thatis most protruding from the axis of the rotation shaft 23 is formed inany one section of the outer peripheral surface. In the drive sectionadjacent to this pressing protrusion 34 b, deviation by the phasedifference (45 degrees) is effected, whereby a plurality of pressingprotrusions 34 b are arranged on the outer peripheral surface of therotary drive member 34 spirally as a whole at intervals corresponding tothe above phase difference.

While in this embodiment the phase difference θ between adjacent drivesections is 45 degrees, it may, for example, be a value corresponding toa divisor corresponding to a rotation angle, such as 20 degrees, 30degrees, 36 degrees, 60 degrees, etc.

Third Embodiment

Next, a third embodiment of the present invention will be described withreference to FIG. 6. In this embodiment, the structures of the rotationshaft 23 and the rotary drive member 24 are completely the same as thoseof the first embodiment. This embodiment differs from the firstembodiment in that a flexible sheet 28 surrounds the liquid supply tube16. End portions of the sheet 28, which surrounds the liquid supply tube16, are attached to a support plate 26 by a fastening member 27. Theposition at which the sheet 28 is fastened to the support plate 26 is ina direction along the rotation tangent on the liquid supply tube 16 sideof the rotary drive member 24 and deviated to a direction opposite tothe direction in which the rotary drive member 24 rotates as seen fromthe liquid supply tube 16 (the liquid supply tube 16 being used as areference).

In this embodiment, the sheet 28 substantially surrounds the liquidsupply tube 16, and is fastened on the side opposite to the liquidsupply tube 16 is moved by its frictional force as the rotary drivemember 24 rotates, and the liquid supply tube 16 is held by the sheet 28so that it may not move in the rotating direction of the rotary drivemember 24, so that twisting, etc. of the liquid supply tube 16 is noteasily generated if there is frictional force between the sheet 28 andthe rotary drive member 24.

The construction of this embodiment regarding the sheet 28 can also beapplied to the case in which the rotary drive member 34 of the secondembodiment is used.

Fourth Embodiment

FIGS. 7 and 8 show the structure of a fourth embodiment of the presentinvention. In this embodiment, a comb-like partition 38 formed of a thinmetal material is provided between the rotation shaft 23 and the rotarydrive member 24, formed in the same manner as in the first embodiment,and the liquid supply tube 16. This partition 38 has a plurality ofslits formed and arranged in the direction in which the liquid supplytube 16 extends. Due to these slits, a plurality of strip-like leadmembers 38 a are formed. A plurality of mounting holes 38 b are formedin the base portion of the partition 38, where no slits are formed. Thepartition 38 is fastened to a support plate 36 by fastening members 37passed through these mounting holes 38 b.

In this embodiment, when the rotary drive member 24 rotates, thepressing protrusion 24 a deforms one of the lead members 38 a of thepartition 38 to indirectly deform the liquid supply tube 16. By makingthe slits relatively deep, the lead members 38 a deform independently,so that it is possible to transmit any change in the position of thecontact portion of the pressing protrusion 24 a to the liquid supplytube 16. The pressing protrusion 24 a of the rotary drive member 24imparts stress to the liquid supply tube 16 through the lead members 38a which do not move in the rotating direction, so that it is possible tomitigate the twisting, deflection, etc. of the liquid supply tube 16 inthe rotating direction of the rotary drive member 24.

The construction of the partition 38 of this embodiment is alsoapplicable to the second embodiment, where the rotary drive member 34 isused. Further, when the partition is formed as a sheet that is flexibleenough, it is possible to form no slits therein and fasten it as anintegral sheet, with its one end being at a position opposite to therotating direction of the rotation tangential direction of the rotarydrive member 24, the sheet being inserted between the rotary drivemember 24 and the liquid supply tube 16.

EMBODIMENTS IN THE SECOND ASPECT OF THE PRESENT INVENTION

In the second aspect of the present invention, there is provided atransfusion pump in which the liquid supply tube is depressed by using athermal deformation material that deforms by receiving or emitting heat.

First Embodiment

Next, a first embodiment in the second aspect of the present inventionwill be described with reference to the accompanying drawings. FIG. 9 isa front view schematically showing the internal structure of atransfusion pump according to the first embodiment of the presentinvention, and FIG. 10 is a left-hand side view schematically showingthe internal structure of the first embodiment. In this embodiment, aplurality of fingers 41 are arranged in the axial direction of a liquidsupply tube 40 formed of a soft synthetic resin or the like. The fingers41 have strip-like heat absorbing portions 41 a extending substantiallyhorizontally, raised portions 41 b formed by bending the heat absorbingportions 41 a and extending vertically, and acting portions 41 c formedby again bending the forward end portions of the raised portions 41 band extending horizontally. The heat absorbing portions 41 a and theraised portions 41 b are formed of a good conductor of heat such ascopper or a copper alloy, and the acting portions 41 c are formed asbimetals in which two kinds of metal having different thermal expansioncoefficients are stacked together.

The above-mentioned liquid supply tube 40 is arranged below the actingportions 41 c, and this liquid supply tube 40 is supported by a supportplate 42. The support plate 42 is mounted on a base 44 through theintermediation of springs 43. In this embodiment, the liquid supply tube40 is a transparent resin tube having a bore of approximately 0.1 mm.While conventional liquid supply tubes have a bore of not less thanapproximately 0.4 mm, in this embodiment, the bore is reduced so as toreduce the size of the drive section and the enhance the flexibility ofthe tube. Further, the wall thereof is thin.

The lower surfaces of the heat absorbing portions 41 a of the fingers 41are respectively in contact with a plurality of heat generating portions45 a formed on the surface of a thermal array 45. The upper surfaces ofthe heat absorbing portions 41 a are in contact with a heat dissipatingmember 46 formed of a good conductor of heat such as copper. The heatdissipating member 46 may be connected to a heat dissipating fin or thelike (not shown). The thermal array 45 is electrically connected toflexible circuit board 47.

As shown in FIG. 11, each heat generating portion 45 a of the thermalarray 45 is formed as follows: a heat resistant layer 451 consisting ofinorganic glass or the like is formed on a ceramic base 450, and a heatgenerating resistant layer 452 consisting of a thin film of Ta₂N isformed on this heat resistant layer 451. The heat generating resistantlayer 451 is in contact with wiring layers 453 and 454 consisting of Alor the like. Further, an insulating protective layer 455 consisting ofsilicon oxide, tantalum oxide or the like is formed on these layers. Thewiring layers 453 and 454 are connected to a head driving circuit of acontrol unit (not shown) through a wiring pattern formed on the flexiblecircuit board 47. The plurality of heat generating portions 45 a,constructed as described above, are arranged on the surface of the base450, and the heat generating portions 45 a thus arranged arerespectively in contact with the heat absorbing portions 41 c of theplurality of fingers 41.

The heat absorbing portions 41 c of the fingers 41 are held between theheat generating portions 45 a of the thermal array 45 and the heatdissipating member 46. To achieve an improvement in terms of assemblyand maintenance, it is desirable that the heat absorbing portions 41 cbe not firmly attached to the heat generating portions 45 a and the heatdissipating member 46 but simply in press contact therewith.

In this embodiment, electricity can be supplied independently to each ofthe plurality of heat generating portions 45 a of the thermal array 45by a control signal from a control unit (not shown). When a heatgenerating portion 45 a generates heat by supplying electricity thereto,the finger 41 which is in contact therewith is heated, and the actingportion 41 c is bent downwards as indicated by the dotted line in FIG.10. As a result of the downward bending of the acting portion 41 c, theliquid supply tube 40 is depressed from above and deforms in such a wayas to be crushed.

When the supply of electricity to the heat generating portion 45 a isstopped, the finger 41 is cooled by the heat dissipating member 46, andthe temperature of the acting portion 41 c is lowered, so that theacting portion is restored to the position indicated by the solid linein FIG. 10 from the position indicated by the dotted line.

As indicated by the dotted lines in FIG. 9, in this embodiment, theacting portions 41 c of the plurality of fingers 41 are periodicallyheated and driven with the phase being staggered little by little, whichmakes it possible for the portion A of the acting portion C whichdepresses the liquid supply tube to be sequentially shifted to the rightas seen in the drawing, whereby it is possible to convey the liquidmedicine in the liquid supply tube 40 to the right as seen in thedrawing.

In this embodiment, the fingers 41 are deformed by thermally drivingthem to convey the liquid medicine in the liquid supply tube 40, so thatthe operating portions are the acting portions 41 c only, and nolarge-sized power drive source or power transmission mechanism isneeded. Thus, the structure is very simple and easily allows a reductionin size. At the same time, the number of parts is reduced, and theassembly is simplified, whereby the production cost can be reduced.Further, since it is not necessary to use a component which involvesmechanical operation such as an electric motor, gear, cam and link, thenoise can be reduced.

While in the above embodiment the acting portions 41 c of the fingers 41are formed as bimetals, it is also possible to form the fingers 41 of ashape memory alloy, the acting portions 41 c being deformed by heating.Examples of the shape memory alloy include a Ti—Ni type alloy, Cu—Zntype alloy, Ni—Al type alloy, Fe—Mg type alloy and other three elementtype alloys. Basically, it is desirable for the thermally deformablemember to be one which undergoes a reversible change. However, it isalso possible to adopt an arrangement in which deformation in onedirection is effected by heating or cooling, and in which thisdeformation is restored to the former state by a mechanism which allowsa reversible deformation such as a spring or a plunger type solenoid.

Second Embodiment

Next, a second embodiment of this invention will be described withreference to FIG. 12. In this embodiment, fingers 41 which aresubstantially the same as those of the first embodiment are used. Athermal array 55 and a cooling member 56 are arranged along the heatabsorbing portions 41 a of the fingers 41, these components coming intocontact with the lower surfaces of the heat absorbing portions 41 a. Aplurality of heat generating portions 55 a are arranged above thethermal array 55, and the heat absorbing portions 41 a of the fingers 41are respectively in contact with these heat generating portions 55 a.

The cooling member 56 consists of a thermal electric device utilizingthe Peltier effect or the like. When electricity is supplied thereto, aplurality of protrusions 56 a formed on the upper surface thereofindependently absorb heat and dissipate it. This cooling member 56 iselectrically connected to a flexible circuit board 57 together with thethermal array 55, and this flexible circuit board 57 is electricallyconnected to a control circuit (not shown).

In this embodiment, electricity is supplied to the heat generatingportions 55 a of the thermal array 55 to generate heat, making itpossible to heat the fingers 41. After the heat generation of the heatgenerating portions 55 a is stopped, electricity is supplied to theprotrusions 56 a of the cooling member 56, whereby heat can be absorbedby the fingers 41. Thus, the deformation of the fingers 41 and therestoration to the original configuration thereof can be effectedquickly and reliably.

Further, the fingers 41 may be deformed either by the heating by thethermal array 55 or by the cooling by the cooling member 56. Forexample, it is possible to deform the fingers 41 through cooling by thecooling member 56 and restore them to the original configuration throughheating by the thermal array 55.

Third Embodiment

Next, a third embodiment of the present invention will be described withreference to FIG. 13. In this embodiment, a finger 61 comprises a heatabsorbing portion 61 a, a connecting portion 61 b and an acting portion61 c. One heat plate 64 an electrothermal element based on the Peltiereffect or the like is in contact with the heat absorbing portion 61 a,and the other heat plate 63 of the electrothermal element is in contactwith a heat dissipating member 60.

The electrothermal element comprises an electrode layer 65 formed on theupper surface of the heat plate 63, and an electrode layer 66 formed onthe lower surface of the heat plate 64, and p-type semiconductor layers67 and n-type semiconductor layers 68 are arranged alternately. That is,the electrothermal element constitutes a module in which, as shown inFIG. 13, electrical connection is repeatedly effected sequentially inthe order: the electrode 65, the n-type semiconductor layers 68, theelectrode layer 66, and the p-type semiconductor layers 67.

Both the electrode layers 65 and 66 are formed so as to effectelectrical connection between adjacent p-semiconductor layers 67 andn-type semiconductor layers 68. When a current is caused to flow betweenthe electrode layer 65 or 66 at the right-hand and left-hand ends,transmission of heat is generated between the heat plates 63 and 64 bythe electrothermal effect. When the current flowing between theelectrode layers 65 and 66 is set to a certain direction, heat istransmitted from the heat plate 65 to the heat plate 66 as is wellknown, and the finger 61 is heated through the heat generation of theheat plate 66. On the other hand, when the direction of the current isreversed, heat is transmitted from the heat plate 66 to the heat plate65, and the heat plate 66 takes heat from the finger 61, whereby thefinger 61 is cooled.

In this way, in this embodiment, the finger 61 can be heated or cooledaccording to the direction of the current flowing through theelectrothermal elements, and the deformation of the acting portion 61 cof the finger 61 and the resotration to the former state thereof can befurthered by the heating and cooling, whereby it is possible to operatethe finger 61 quickly and reliably to depress the liquid supply tube asin the above-described embodiment. A plurality of combinations offingers and electrothermal elements as shown in FIG. 13 are arranged inthe direction in which the liquid supply tube extends, and, by drivingeach electrothermal element, it is possible to individually control aplurality of fingers.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be describedwith reference to FIGS. 14 through 16. In this embodiment, a pluralityof fingers 62 made of the same material as the fingers 61 of the thirdembodiment are in contact with the electrothermal elements based on thePeltier's effect or the like. In this embodiment, the base portion ofeach finger 62, formed in a strip-like configuration, is divided into afirst branch portion 62 a and a second branch portion 62 b. The firstbranch portion 62 a is in contact with an upper heat plate 64′, and thesecond branch portion 62 b is in contact with a lower heat plate 63′, asin the above-described third embodiment. However, a plurality ofelectrothermal module rows are arranged in a direction perpendicular tothe plane of FIG. 14 and connected in a matrix-like fashion; the firstbranch portion 62 a and the second branch portion 62 b of a finger 62are connected different electrothermal module rows.

The electrothermal elements comprises electrode layers 65′ and 66′ heldbetween the heat plates 63′ and 64′, p-type semiconductors 67′ andn-type semiconductors 68′. The electrothermal element comprises aplurality of electrothermal module rows in which electrical connectionis repeatedly effected in the order: the electrode layer 65′, the n-typesemiconductor layers 68′, the electrode layer 66′, and the p-typesemiconductor layers 67′ along the direction in which the first branchportion 62 a and the second branch portion 62 b extend. The plurality ofelectrothermal module rows are arranged in a direction perpendicular tothe plane of FIG. 14. As shown in FIG. 15, these plurality ofelectrothermal module rows are electrically connected in the horizontaldirection perpendicular to the direction in which the first branchportion 62 a and the second branch portion 62 b extend such thatconnection is repeatedly effected in the order: the electrode layers65′, the n-type semiconductor layers 68′, the electrode layers 66′, andthe p-type semiconductor layers 67′.

In FIG. 15, the portions of the electrothermal module rows of theelectrothermal elements which correspond to four fingers are indicatedby numerals with numbers 1 through 4 in parentheses. Each finger is inthermal contact with three electrothermal module rows. That is, of thefour fingers 62, the first branch portion 62 a(1) is in contact with theelectrode layers 66′(1) through the intermediation of the heat plate64′, and this n-type semiconductor layer 68′ is joined to the electrodelayer 65′(0) on the heat dissipating member 69 a. Further, the electrodelayer 66′(1) is also joined to the p-type semiconductor layer 67′, andthis p-type semiconductor layer 67′ is joined to the electrode layer65′(1) formed on the heat plate in contact with the second branchportion 62 b(1) of the first finger 62. This electrode layer 65′(1) isalso joined to another n-type semiconductor layer 68′, and this n-typesemiconductor layer 68′ is joined to the electrode layer 66′(2) formedon the lower surface of the heat plate 64′ in contact with the firstbranch portion 62 a(2) of the second finger. Further, this electrodelayer 66′(2) is also joined to another p-type semiconductor layer 67′,and this p-type semiconductor layer 67′ is joined to the electrode layer65′(2) formed on the heat plate 63′ in contact with the second branchportion 62 b(2) of the second finger. Similarly, regarding the thirdfinger and the fourth finger also, they are in contact with joint unitsof the electrode layers 65′(3), 65′(4), 66′(3), 66′(4) and the p-typesemiconductor layer 67′, the n-type semiconductor layer 68′.

With respect to each of the n-type semiconductor layers 68′ and thep-type semiconductor layers 67′ shown in FIG. 15, the electrothermalmodule row shown in FIG. 14 extends in a direction perpendicular to theplane of the drawing. In these electrothermal module rows, the p-typesemiconductor layers 67′ and the n-type semiconductor layers 68′ arearranged alternately and repeatedly, as shown in FIG. 14. In theelectrothermal module row in which the n-type semiconductor layer 68′appears in FIG. 15 (the row extending in the direction of the plane ofFIG. 15), the position of the n-type semiconductor layer and theposition of the p-type semiconductor layer are reverse when comparedwith the electrothermal module in which the p-type semiconductor layer67′ appears in FIG. 15. That is, in the two adjacent electrothermalmodule rows, the conduction types of the semiconductor layers includedtherein are opposite to each other.

As shown in FIG. 15 and 16, the first branch portion 62 a and the secondbranch portion 62 b of the finger 62 are arranged so as to behorizontally deviated from each other so that they are two-dimensionallypartly overlap. A part of the second branch portion 62 b of the finger62 two-dimensionally overlap the first branch portion of the adjacentfinger, and a part of the first branch portion 62 a of the finger 62two-dimensionally overlap the second branch portion of the adjacentfinger.

In this embodiment, in the electrothermal module row at the left-handend shown in FIG. 15, of the electrode layers 65′(0) (a plurality ofthem are divisionally arranged in the direction perpendicular to theplane of the drawing), that electrode layer 65′(0) which is at thebottom with respect to the plane of the drawing (the left-hand end inFIG. 14) is supplied with high potential, and that electrode layer65′(0) which is nearest to the reader with respect to the plane of thedrawing (the right-hand end in FIG. 14) is supplied with low potential,whereby, in the electrothermal module, it is possible, as shown in FIG.14, to flow a current in a zigzag fashion through the p-typesemiconductor layers 67′ and the n-type semiconductor layers 68′arranged alternately between the electrode layer 65′(0) and theelectrode layer 66′(1), with the result that heat is absorbed from theheat dissipating member 69 a and transmitted to the first branch portion62 a(1) of the first finger to heat the first finger.

Next, when the supply of electricity to the electrode layer 65′(0) isstopped and electricity is supplied to the electrode layer 65′(1) in asimilar manner, the next electrothermal module row (the second row fromthe left-hand side of FIG. 15) formed between the electrode layer 65′(1)and the electrode layer 66′(1) absorbs heat from the first branchportion 62 a(1) and transmits heat so as to dissipate it to the secondbranch portion 62 b(1). The still next electrothermal module row formedbetween the electrode layer 65′(1) and the electrode layer 66′(2)conversely absorbs heat from the second branch portion 62 b(1) of thefirst finger and transmits heat so as to dissipate it to the firstbranch portion 62 a(2) of the second finger. Due to this arrangement,heat is transmitted generally from the first finger to the secondfinger; the second finger is heated simultaneously with the cooling ofthe first finger.

Similarly, when the supply of electricity to the electrode layer 65′(1)is stopped and electricity is supplied to the electrode layer 65′(2),the second finger is cooled, and the third finger is heated. In thisway, it is possible to cool the once heated finger and, at the sametime, gradually heat the adjacent finger. In this embodiment, heat istaken from a previously heated finger and heat is supplied to the fingerto be heated next, so that it is possible to successively operate thefingers solely through transmission of heat, whereby it is possible tocontrol and drive very efficiently. Although it is possible toindividually provide each finger with an electrothermal module fordrive, it is possible, as in this embodiment, to operate the fingerswhile effecting heat exchange between adjacent fingers, whereby there isno need to effect heat exchange between the interior and exterior of thedevice, thereby preventing overheating, condensation, etc. of thedevice.

In this embodiment, a plurality of electrothermal module rows areconnected together in a direction perpendicular to the plane of FIG. 14,as shown in FIG. 15. However, instead of this arrangement, it ispossible to simply arrange the individual electrothermal units,connected together as shown in FIG. 15, in parallel in a directionperpendicular to the plane of the drawing, and to supply electricity toeach of the electrothermal units, thereby achieving the same effect.

Further, in this embodiment, when the electrode layer to whichelectricity is supplied is changed, heat is transmitted from the firstbranch portion, which has been heated, to the second branch portion, andfrom the second branch portion to the first branch portion of theadjacent finger. However, it is also possible to simply stop the heatingof the first branch portion by the Peltier effect and to generatetransmission of heat from the second branch portion to the first branchportion of the adjacent finger. As in this embodiment, this method alsomakes it possible to simultaneously effect the cooling of the fingerafter the stopping of heating and the heating of the adjacent finger.

EMBODIMENTS IN THE THIRD ASPECT OF THE PRESENT INVENTION

In the third aspect of the invention, there is provided a liquid supplytube for use in a transfusion pump. It relates to the structure of aliquid supply tube formed by firmly fixing together two componentmembers.

First Embodiment

FIG. 17 is a perspective view schematically showing the structure of aliquid supply tube according to the present invention, and FIG. 18 is asectional view showing the structure of the liquid supply tube. Thisliquid supply tube 80 is formed by joining a hard plate-like member 81formed of a hard synthetic resin with a flat elastic plate-like member82 formed of an elastic, flexible synthetic resin at joint surfaces B1in the edge portions with respect to the width direction. The joining iseffected by adhesion using an adhesive, welding using heat oroscillation (ultrasonic wave), etc.

The hard plate-like member 81 comprises an extended groove portion 81 aat the center with respect to the width direction having a semi-circularsectional configuration, and a pair of flat portions 81 b protruding oneither side of the extended groove portion 81 a. Inside the extendedgroove portion 81 a, there is formed a liquid passage B2 defined betweenthe groove portion and the inner surface of the elastic plate-likemember 82.

In this liquid supply tube 80, a liquid passage B2 for liquid medicineis secured by the hard plate-like member 81 having the extended grooveportion 81 a, and liquid medicine can be conveyed by deforming theflexible elastic plate-like member 82. That is, as shown in FIG. 19, theelastic plate-like member 82 is depressed from outside by a depressionmember 83 such as a roller or finger, whereby it is possible to pressthe elastic plate-like member against the inner surface of the extendedgroove portion 81 of the hard plate-like member 81; by moving thedepressed portion in the direction in which the liquid passage B2extends, it is possible to move the liquid medicine inside the liquidsupply tube.

For example, when forming a rotary type transfusing device, the hardplate-like member 81 is curved in an arcuate form along the rotatingdirection of the rotation arm to which a roller is attached, and theelastic plate-like member 82 is joined so as to be arranged inside thecurved form. When forming a finger type transfusing device, a linearliquid passage B2 is formed as shown in FIG. 17, and fingers arearranged on the elastic plate-like member 82 side.

In this case, when the forward end portion 83 of the depression membersuch as roller or finger has a curved configuration substantiallycorresponding to the inner surface of the extended groove portion 81 aof the hard plate-like member 81, it is possible to deform the elasticplate-like member 882 so as to be substantially in conformity with theinner surface of the extended groove portion 81 a through the depressionof the depression member 83, so that it is possible to control andmaintain the speed at which the liquid medicine is supplied with highaccuracy and stability.

In the above-described liquid supply tube, the hard plate-like member 81and the elastic plate-like member 82 can be easily and separately formedby injection molding, extrusion, or the like; even when the size of theliquid passage B2 is small, the production is easier as compared withthe case of a tubular member produced by extrusion or the like. Accuracyin form is easily achieved if the diameter of the liquid passage B2 issmall. Further, a reduction in production cost can be achieved.

Further, since the component members may have a simple configuration,there is little limitation in terms of material. In particular, thecharacteristics of the elastic plate-like member 82, such as elasticity,flexibility and durability can be improved. In this embodiment, theelastic plate-like member 82 has a parallel and flat configuration, sothat it is easy to produce. The production can be conducted with a highquality material.

Further, when compared with the conventional tubular liquid supply tube(which is the strongest against external forces), the requisite stressfor closing the liquid passage is smaller. Further, it is not apt toassume an unnatural closing configuration, so that it is possible toreduce the driving force, and reduce the size of the driving mechanismand the energy consumed.

While in the above-described embodiment one of the component members isformed as a hard plate-like member 81, it is also possible to form bothcomponent members of an elastic material by supporting by a supportmember or the like. Further, it is not absolutely necessary for thecomponent members to be plate-like members. For example, instead of thehard plate-like member 81, it is also possible to use a block memberhaving an extended groove portion on its surface. Further, instead ofthe elastic plate-like member 82, it is possible to adopt members ofvarious configurations partly equipped with a flat plate-like portion.

In this embodiment, one of the two component members forming the liquidsupply tube 80, the hard plate-like member 81 and the elastic plate-likemember 82, i.e., the elastic plate-like member 82, is formed as aplate-like member having elasticity. Instead of thus providing one ofthe component members with a plate-like portion having elasticity, it isalso possible to provide one of the component members with a plate-likeportion having little elasticity. In this case, the depression member 83and the plate-like portion are firmly attached to each other by adhesionor the like and, in this condition, the depression member 83 is operatedto increase and decrease the sectional area of the liquid passage B2 tothereby convey the liquid medicine.

Second Embodiment

Next, a second embodiment of this invention will be described withreference to FIGS. 20, 21 and 22. As shown in FIG. 20, the liquid supplytube 80′ of this embodiment is formed by joining together a hardplate-like member 81 and an elastic plate-like member 82 similar tothose of the first embodiment. On the inner surface of the elasticplate-like member 82 and at positions opposite to the extended grooveportion 81 a, a plurality of elastic protrusions 84 are arranged alongthe liquid passage B2. As shown in FIG. 21, these elastic protrusions 84have a surface configuration substantially in conformity with the innersurface of the extended groove portion 81 a. As shown in FIG. 22, whenthe outer surface of the elastic plate-like member 82 is depressed by adepression member 83, the elastic protrusion 84 abuts substantiallysnugly against the inner surface of the extended groove portion 81 a andacts so as to close the liquid passage B2.

In this embodiment, the liquid passage B2 can be easily closed by theelastic protrusion 84, so that it is possible to reduce the drivingforce of the depression member and achieve a reduction in the size ofthe device and the power consumed. Further, since the liquid passage B2can be closed by the elastic protrusion 84, the liquid passage B2 can beeasily closed if the elastic plate-like member 82 is thin, so that it ispossible to enhance the follow capacity with respect to the deformationof the elastic plate-like member 82.

Further, since in this embodiment the liquid passage B2 can be easilyclosed, the speed at which the liquid medicine is supplied can becontrolled with accuracy, thereby making it possible to convey theliquid medicine in a stable manner. Further, since the deformationamount of the elastic plate-like member 82 can be reduced, there is lesslimitation in terms of the material of the elastic plate-like member 82and, at the same time, the durability of the liquid supply tube can beenhanced.

Due to their elasticity, the elastic protrusions 84 deform with theelastic plate-like member 82, so that it is possible to close the liquidpassage B2 more flexibly. The elastic protrusions 84 may be formedintegrally with the elastic platelike member 82. Further, instead of theelastic protrusions 84, it is also possible to provide protrusionsformed of a less elastic material such as metal.

In this embodiment, the liquid in the tube can be conveyed by depressingthe liquid supply tube 80′ by the depression member 83 as shown in FIG.22. Instead of the elastic protrusions 84 arranged in the liquid supplytube 80′, it is also possible to use magnetic members of substantiallythe same configuration; these magnetic members are vertically moved asseen in FIG. 22 by an electromagnet provided outside, whereby it ispossible to convey the liquid medicine in the liquid supply tube 80′while deforming the elastic plate-like member 82. The electromagnet isarranged, for example, outside and below the extended groove portion 81a shown in FIG. 22, whereby the above-mentioned magnetic membersfastened to the inner side of the elastic plate-like member 82 can bedriven.

As described below, the liquid supply tube of the first and secondembodiment can be used in the liquid medicine conveying section of aperistaltic transfusing device. Further, it can be used as a tube forconveying an arbitrary liquid; it can be used for the purpose offincreasing and decreasing the flow section of a liquid by the mechanicalstress or the electromagnetic stress as described above. In particular,is can also be used as a part of a valve body for cutting off thefeeding out of a liquid.

Next, an example of the construction of a transfusing device(transfusion pump) using the liquid supply tube 80′ of theabove-described second embodiment will be described with reference toFIGS. 23, 24 and 25. On either side of the liquid supply tube 80′,depression levers 92 each including a thermally deformable portion 92 aconsisting of bimetal are arranged alternately respectively incorrespondence with the elastic protrusions 84 of the liquid supply tube80′. Fastened to the forward end portion of the thermally deformableportion 92 a of each depression lever 92 is a depression piece 94 havinga gently protruding curved surface. The base portion of each depressionlever 92 is divided into upper and lower sections 92 b and 92 c.

As shown in FIG. 24, a common electrothermal element 95 utilizing thePeltier effect or the like exists between the upper section 92 b of onedepression lever 92 and the lower section 92 c of another depressionlever 92 adjacent thereto on one side of the liquid supply tube. Theheat dissipating portion 95 a of the electrothermal element 95 isthermally in contact with the upper section 92 b, and the heat absorbingportion 95 b of the electrothermal element 95 is thermally in contactwith the lower section 92 c of the adjacent depression lever. Thus, oneither side of the liquid supply tube, a plurality of electrothermalelements 95 existing between adjacent depression levers are arranged.

By causing a current to flow in a predetermined direction, each of theelectrothermal elements 95 absorbs heat from the heat absorbing portion95 b shown in FIG. 23 and dissipates it from the heat dissipatingportion 95 a. In this way, each depression lever 92 is thermally incontact with two electrothermal elements: the electrothermal element incontact with the upper section 92 b and the electrothermal element incontact with the lower section 92 c. Thus, when electricity is suppliedto the electrothermal element 95 which is in contact with the uppersection 92 b of the depression lever 92, the depression lever 92 isheated and, as shown in FIG. 25, the thermally deformable portion 92 aof bimetal structure is downwardly bent, and the depression piece 94downwardly depresses the outer surfaces of the elastic plate-like member82. Then, the elastic plate-like member 82 depressed by the depressionpiece 94 downwardly depresses the elastic protrusion 84 provided insideto thereby close the liquid passage B2.

Next, the current flowing to the electrothermal element 95 in contactwith the upper section 92 b of the depression lever 92 is cut off and,at the same time, a current is caused to flow to the electrothermalelement 95 in contact with the lower section 92 c. Then, the depressionlever 92, which has been heated, starts to be cooled. As the temperatureof the depression lever 92 is gradually lowered, the thermallydeformable portion 92 a is gradually restored to the original state, andthe elastic protrusion 84 retreats upwards, the liquid passage B2starting to gradually open. At this time, the electrothermal element 95which is in contact with the lower section 92 c of the depression lever92 comes into contact with the upper section 92 b of the adjacentdepression lever 992 and heats this adjacent depression lever 92, sothat the thermaly deformable portion 92 a of this adjacent depressionlever 992 is gradually bent and starts to close the liquid passage B2.Thus, when a certain depression lever 92 is heated, another depressionlever on the upstream side of the liquid passage is cooled, and when thecertain depression lever 92 is cooled, another adjacent depression lever92 on the downstream side of the liquid passage is heated, so that thedepression levers 92 arranged from the upstream side to the downstreamside of the liquid passage B2 are sequentially heated and cooled, andthe position of the liquid passage B2 which is closed by the depressionlever 92 is gradually displaced downwards.

Since a plurality of depression levers 92 are arranged on either side ofthe liquid supply tube 80′, synchronous control is effected with thephase of the heating/cooling timing for the depression levers arrangedon one side of the liquid supply tube 80′ being shifted from the phaseof the heating/cooling timing for the depression levers arranged on theother side of the liquid supply tube 80′, whereby delay in the thermalresponse time of the individual depression levers 92 is avoided, therebymaking it possible to convey the liquid medicine in the liquid supplytube 80′ downwardly.

In this embodiment, the depression levers having a bimetal structure aredeformed by heating and cooling of the electrothermal elements, so thatthere is not much mechanically operated portion, and it is possible toprovide a driving mechanism having less noise, relatively free fromfailure and having high durability. Further, since the heat absorbingportions and heat dissipating portions of the electrothermal elementsare joined to adjacent depression levers, and the depression levers areheated and cooled efficiently, so that there is provided a high energyefficiency, and the power consumed is reduced. Further, since the liquidsupply tube is depressed by depression levers responding to heat, thedepressing operation of the depression levers is effected smoothly, andno abrupt motion is generated, so that the durability of the liquidsupply tube is further improved.

While in this construction example an electrothermal element is used asthe heating/cooling means, it is also possible to adopt other types ofheating means, such as an electric heater, and cooling means, such asones using a heat dissipating plate, refrigerant, etc. Further, while inthis construction example a bimetal structure is adopted as the heatresponsive material, it is also possible to adopt other type of heatresponsive material which reversibly deforms by heating and cooling,such as shape memory alloy.

While this construction example consists of a peristaltic transfusingdevice (transfusion pump) formed by using the liquid supply tube shownwith reference to the second embodiment and, in particular, a fingertype transfusion pump structure, it is also possible to adopt anotherfinger type driving mechanism as the transfusing device using the firstor second embodiment. Further, by providing a liquid supply tube in anarcuate form and a mechanism for rotating a rotating arm with roller atits both ends, it is possible to form a rotary type transfusion pump.

Third Embodiment

Next, a third embodiment of the liquid supply tube of the presentinvention will be described with reference to FIG. 26. This liquidsupply tube 100 comprises a U-shaped block member 101 formed of a hardplastic or the like, and an elastic sheet attached to the upper surfaceof the block member 101. The block member 101 comprises a prism-likecentral portion, and a pair of end portions provided at the ends thereofand protruding downwardly. On the upper surface of the block member 101,there is formed an extended groove portion 101 a having a semi-circularcross-sectional configuration. This extended groove portion end near theends of the block member 101 and does not extend therethrough. From theend portions of the extended groove portion 101 a, there extenddownwardly connection holes 101 b, which reach the lower surface of theend portions.

In this embodiment, the end portions of the liquld supply tube 100 isformed integrally with the block member 101, so that it is possible toappropriately design the end portion configuration for connection to atransfusion tube or the like without increasing the number of parts.While in this embodiment the end portions of the liquid supply tube 100have a prism-like configuration, it may also have, for example, atubular configuration, in conformity with the end portion configurationof the transfusion tube. Further, screw portions may be providedthereon.

FIG. 27 shows the configuration of a joint member 103 for joining aliquid supply tube with a semi-circular sectional configuration to atransfusion tube with a circular sectional configuration for use in thecase in which no special end portion configuration as shown in FIG. 26as in the case of a liquid supply tube having a circular sectionalconfiguration as shown in FIGS. 24 and 25. An end portion 103 a of thejoint member 103 has a semi-circular cross-sectional configuration thatcan be fitted onto a liquid supply tube, and an end portion 103 bthereof has a circular configuration that can be fitted onto atransfusion tube.

EMBODIMENTS IN THE FOURTH ASPECTS OF THE INVENTION

In the fourth aspect of the present invention, there is provided atransfusion pump which performs transfusion in a stable manner with aplurality of fingers, with the liquid medicine being pressurized on theupstream side.

FIG. 28 a sectional view schematically showing the construction of atransfusing device according to a first embodiment of the presentinvention. In this embodiment, liquid medicine is injected into aballoon 110 formed of an elastic material such as synthetic rubber, andthe balloon 110 is held between upper and lower pressing plates 111 and112 and pressurized at a predetermined pressure. The balloon 110 isconnected to a flexible liquid supply tube 116 formed of a syntheticresin, and a support plate 121 is arranged on one side of this liquidsupply tube 116. In the liquid supply tube 116, on the side opposite tothe support plate 121, the forward end portion of a valve member 122constituting an inlet valve and the forward end portion of a valvemember 123 constituting a discharge valve are opposed to each other atan interval. Between the valve members 122 and 123, four pushers 124,125, 126 and 127 are arranged in the direction in which the liquidsupply tube 16 extends.

The valve members 122 and 123 and the four pushers 124, 125, 126 and 127are caused to move toward and away from the liquid supply tube 16 byplunger type micro solenoids 128 (there are two of them) and 129 (thereare four of them).

FIG. 29 is a right-hand side view of FIG. 28, showing the constructionof the section for pressurizing the balloon 110. The balloon 110 isplaced on the pressing plate 111 which is attached to the case of thetransfusing device or which constitutes the bottom plate of the case,and the pressing plate 112 is placed on the balloon 110. The pressingplate 112 is connected to lower edge portions 114 a of a cover 114having a U-shaped sectional configuration by a rubber band 113. Thus,the balloon 110 is pressurized from above and below by the pressingplates 111 and 112, whereby a predetermined pressure is applied to theliquid medicine.

FIGS. 30 through 33 illustrate how the valve members 122 and 123 and thepushers 124, 125, 126 and 127, which constitute the transfusion pump,operate. First, as shown in FIG. 30, the valve member 123 on thedownstream side protrudes toward the tube 116 and the valve member 122on the upstream side and the pushers 124, 125, 126 and 127 are all drawnback. In this condition, the discharge valve is closed by the valvemember 123.

Next, as shown in FIG. 31, the valve member 122 protrudes toward theliquid supply tube 116, and the upstream side of the liquid supply tube116 is shut. Here, liquid medicine pressurized by the pressurizing meansis trapped in that section of the liquid supply tube 116 which isbetween the valve member 122 and the valve member 123.

Next, as shown in FIG. 32, the valve member 123 is drawn back and thepusher 124 protrudes. When the valve member 123 is drawn back, thevolume of that section of the liquid supply tube 116 which has beendepressed by the valve member 123 increases, so that there is a fearthat reverse flow of liquid medicine is generated in the liquid supplytube 116 backwards from the downstream side from the portion which hasbeen depressed by the valve member 123 or that the liquid medicine willbe partially under negative pressure to generate a bubble. In view ofthis, the increase in the volume of the liquid supply tube due to thedrawing back of the valve member 123 (and the change in pressure insidethe tube attributable thereto) is compensated for by the protrusion ofthe pusher 124, thereby mitigating the generation of negative pressure,bubbles, etc.

Next, as shown in FIG. 33, the pushers 125, 126 and 127 are caused toprotrude to push out the liquid medicine inside the liquid supply tube116 downwardly, whereby the liquid medicine is discharged. Although allthe pushers 125, 126 and 127 may be simultaneously caused to protrude,it is more desirable for the pushers to be sequentially protruded withshifted timing starting from the upstream side pusher 125 and endingwith the downstream side pusher 127 in order to convey the liquidmedicine more smoothly.

When the discharge of the liquid medicine has been completed asdescribed above, the valve member 123 is caused to protrude again asshown in FIG. 30 to close the discharge valve, and the upstream sidevalve member 122 and the pushers 124, 125, 126 and 127 are drawn back totake liquid medicine from the upstream side into the liquid supply tube116.

It is desirable that the valve members 122 and 123 and the pushers 124,125, 126 and 127 be formed so as to completely close the liquid supplytube 116 in order that the flow of liquid medicine in the liquid supplytube 116 may be completely cut off when they protrude. However, even ifthe liquid supply tube 116 is not completely closed by the valve membersand the pushers and the flow of liquid medicine is not completely cutoff, the same effect as described above can be obtained if the closedstate of the liquid supply tube 116 is substantially complete, and theinfluence of the pressure of the liquid medicine on the upstream side ishardly transmitted to the downstream side.

Regarding the valve member 122 in FIGS. 32 and 33, and the pushers onthe upstream side when the pushers on the downstream side areprotruding, they need not be protruding as shown in the drawings sincethe pressure of the liquid medicine is cut off by the pushers on thedownstream side cutting off the interior of the liquid supply tube 116;they may be drawn back immediately after the protruding of the pusherson the downstream side.

While in the above pump structure formed by the support plate, the valvemembers and the pushers, operation is effected by the two valve membersand the four pushers opposed to the support plate, there is no need todiscriminate between the valve members constituting the inlet valve andthe discharge valve, and the pushers constituting the dischargemechanism; they may all consist of the same members. The minimum numberof these valve members and pushers is three.

Further, while in the above embodiment the valve members and the pushersare driven by solenoids, the valve members and pushers may also bedriven by mechanical parts such as cams or air cylinders.

In this embodiment, the liquid medicine is constantly pressurized at aconstant pressure by the balloon and the pressurizing mechanism (111,112, 113 and 114) for the balloon, and a fixed amount of thispressurized liquid medicine is Abrought into the pump at one time by thevalve members and pushers, and the liquid medicine thus taken in isdischarged. Thus, the minimum requisite number of valve members andpushers is three, so that the number of parts can be substantiallyreduced as compared with the conventional finger type transfusion pump.

There is no need for the liquid medicine to be pressurized at a fixedpressure; for example, the liquid pressurizing means may be formedsolely by the balloon 110. Further, the liquid pressurizing means may beof a piston type in which, for example, a predetermined stress isapplied to the rod of the cylinder, or one which utilizes an aircylinder.

Further, since the liquid medicine is taken in and discharged from thepump formed by the support plate, the valve members and the pushers, theamount of liquid medicine discharged is determined with high accuracy,and the speed at which the liquid medicine is injected can be set withhigh accuracy. Further, it is possible to inject a minute amount ofliquid medicine. In this case, to increase the speed at which the liquidmedicine is supplied, the operating period of the valve members and thepushers is reduced to thereby effect high speed operation.

In this method, by changing the number and width of the valve membersand the pushers, it is possible to easily adjust the amount of liquidmedicine discharged at one time. Further, it is possible to control thesupply pressure of the liquid medicine by the operating period of thevalve members and the pushers, not depending on the pressurizing forcefor the liquid medicine on the upstream side. Thus, it is possible tosupply the liquid medicine at high pressure.

In the conventional peristaltic transfusing device, the liquid supplytube is endowed with a sufficient degree of elasticity, so that theliquid supply tube deforms when depressed by the fingers incorrespondence with the positions of the fingers, whereby the liquidmedicine is conveyed. In this embodiment, in contrast, pressurizedliquid medicine is substantially trapped in a predetermined region ofthe liquid supply tube, and this trapped liquid medicine is discharged,so that there is no need for the liquid supply tube to have elasticity;it has only to have a sufficient degree of flexibility. Thus, in thisembodiment, the wall of the liquid supply tube may be thin, so that thepower loss of the pump is reduce, thereby enhancing the pump efficiency.Further, the diameter of the liquid supply tube can be easilydiminished, whereby it is possible to easily inject a minute amount ofliquid medicine.

EMBODIMENTS IN THE FIFTH ASPECT OF THE INVENTION

The fifth aspect of this invention relates to the construction of atransfusion pump equipped with a diaphragm which performs transfusionwith the liquid medicine being pressurized on the upstream side.

Next, an embodiment of the transfusing device of this invention will bedescribed with reference to FIGS. 34 through 38. In this embodiment, apower source 131 such as a battery and a circuit board 132 on which anelectronic circuit including a control circuit is formed areaccommodated in a case 130. Further, a transfusion pump controlled bythe control circuit is formed.

This transfusion pump comprises a diaphragm 133 consisting of metal,semiconductor, ceramic, synthetic resin or the like and formed bystamping, photolithography, sintering, resin molding or the like, and abase 134 which consists of a similar material and is formed by any oneof the above-mentioned techniques or machining and which has an inlethole 134 a and a discharge hole 134 b.

The diaphragm 133 comprises a valve portion 133 a formed at a positioncorresponding to the inlet hole 134 a of the base 134, a dischargedeformation portion 133 b formed at the center, and a valve portion 133c formed at a position corresponding to the discharge hole 134 b of thebase 134. The valve portions 133 a and 133 c are formed as thick walledportions surrounded by thin walled portions that are easily deformed. Atthe lower ends thereof, there are formed valve body portions consistingof elastic members formed of synthetic rubber or the like such assilicone rubber which does not react with chemicals. These valve bodyportions are firmly attached to the diaphragm 133 by adhesion, coatingor the like.

The valve portions 133 a and 133 b are formed such that they open andclose the inlet hole 134 a and the discharge hole 134 b by microactuators 135 and 137, respectively, mounted on the circuit board 132.Further, the discharge deformation portion 133 b is formed as a thinwalled portion having a large area, and is similarly largely deflectedto the interior and exterior of the pump chamber by a micro actuator 136mounted on the circuit board 132.

The micro actuators 135, 136 and 137 may consist of various plunger typesolenoids, piezoelectric actuators, micro motors, air cylinders,hydraulic cylinders or the like. Further, around the discharge hole 134b of the base 134, there are mounted a flow rate sensor 138 and a bubblesensor 139.

Connected to the inlet hole 134 a of the base 134 is a liquid medicinepressurizing mechanism consisting of an elastic balloon 110.

First, as shown in FIG. 35, in this embodiment, the valve portion 133 aand the discharge deformation portion 133 b is kept at the raisedposition, and the valve portion 133 c is lowered by pressing it by themicro actuator 137 to close the discharge hole 134 b. In this condition,liquid medicine is introduced into the pump from the balloon 110 (notshown) at a predetermined pressure. Next, as shown in FIG. 36, the valveportion 133 a is lowered by depressing it by the micro actuator 35 toclose the inlet hole 134 a. In this condition, the liquid medicineintroduced into the pump is trapped therein at the pressure at which ithas been supplied.

Next, as shown in FIG. 37, the depression by the micro actuator 137 iscanceled, and the valve portion 133 is restored to the raised positionby the elasticity of the diaphragm 133 to open the discharge hole 134 b.At this time, to prevent reverse flow of the liquid medicine due to theraising of the valve portion 133 c, the micro actuator 136 is operatedto slightly push down the discharge deformation portion 133 b.

Next, as shown in FIG. 38, the micro actuator 136 is operated to greatlypush down the discharge deformation portion 133 b to discharge theliquid medicine in the pump through the discharge hole 134 b. When thedischarge of the liquid medicine has been completed, the valve portion133 c is depressed by the micro actuator 137 to close the discharge hole134 b again. After this, the valve portion 133 a is raised to open theinlet hole 134 a, and the discharge deformation portion 133 b isrestored to the original state, whereby the condition as shown in FIG.35 is restored.

In this embodiment also, as in the embodiment in the fourth aspect ofthe invention, the liquid medicine can always be conveyed in apressurized state, so that no fluctuations in the pressure of the liquidmedicine with passage of time are generated, and the device can be usedin a stable state. Further, the liquid medicine is not placed undernegative pressure, and few bubbles are generated. Further, the flow ratecan be controlled with high accuracy, and it is possible to discharge aminute amount of liquid medicine. Further, the size of the device can beeasily reduced.

In the above embodiment, by making the diaphragm 133 and the base 134detachable with respect to the case 130, replacement, cleaning,inspection, etc. are facilitated.

EMBODIMENTS COMMON TO THE ASPECTS OF THE INVENTION

Finally, a specific example of the general construction of a transfusingdevice which is commonly applicable to the above aspects of theinvention will be described with reference to FIGS. 39 and 40. FIG. 39is a schematic diagram showing the general construction of thetransfusing device. A discharge mechanism 140, constructed as shown withreference to the above-described embodiments, is arranged along theliquid supply tube 116 that can be connected to a liquid medicinecartridge 141 containing a pressurizing mechanism composed of theballoon 110 and the pressing plates 111 and 112. On the downstream sideof the discharge mechanism 140, there is mounted a micro sensor 142,which detects the presence of a bubble in the liquid supply tube 116,the stopping of the liquid medicine in the liquid supply tube 116, etc.

The operating section such as the discharge mechanism 140 is controlledby a central control unit 143. The central control unit 143 transmits acontrol signal to a drive circuit 144, and operates the dischargemechanism 140 by an actuator 145 formed as a solenoid, micro actuator orthe like. The actual operating speed of the discharge mechanism 140 isdetected by a detecting circuit 149 consisting of an optical sensor orthe like. The drive signal transmitted from the drive circuit 144 to theactuator 145 and the detection signal transmitted from the detectingcircuit 149 are introduced to a pulse counter 146, and the differencetherebetween is counted by the pulse counter and fed back to the centralcontrol unit 143.

A predetermined potential is supplied to the drive circuit 144 from apower source circuit 148 which is supplied with a predeterminedpotential which is supplied with power from a power source 147 such as abattery.

Connected to the central control unit 143 are an operating section 151,an alarm device 152, an external terminal connecting section 153, and adisplay device 154. When during the conveyance of the liquid medicine abubble in the liquid medicine or the stopping of liquid medicine isdetected by the above micro sensor 142, the central control unit 143gives an alarm from the alarm device 152 consisting of a speaker or thelike. Further, the central control unit 143 inputs signals from othercontrol apparatus or measurement apparatus from the external terminalconnecting section 153, and, in accordance with the signals, controlsthe injection speed, injection time, etc. of the liquid medicine.Further, the central control unit 143 constantly displays the liquidmedicine injection speed, integral of injection time, etc. through thedisplay device 154.

FIG. 40 is a schematic diagram showing the appearance of thistransfusing device. There is provided a plastic case 150 designed to beof a size which can be held by hand, and the liquid supply tube 116 isinserted into the case. The discharge mechanism 140 and the micro sensor142 arranged along the liquid supply tube 116. Further, the centralcontrol unit 143, the drive circuit 144, the actuator 145, the pulsecounter 146 and the power source circuit 148 are formed on the circuitboard to form a circuit block 155. Further, the case 150 accommodatesthe power source (battery) 147 and the alarm device 152. On the surfaceof the case, there are arranged the operating section 151 consisting ofa plurality of push-button switches, the external terminal connectingsection 153 consisting of mini-jacks or the like, and the displaysection 154 consisting of a liquid crystal panel or the like.

In the upper section of the case 150, there is provided an opening 150a, into which the liquid medicine cartridge 141 can be detachablyinserted. As shown in FIG. 39, the liquid medicine cartridge 141 isprovided with a joint section 141 a. When the liquid medicine cartridge141 is inserted into the opening 150 a of the case 150, it isautomatically connected to a joint receiving section (not shown)provided inside the case 150. The forward end of the liquid supply tube116 is connected to the joint receiving section. When the liquidmedicine cartridge 141 is attached, the joint section 141 a thereofcommunicates with the liquid supply tube 116.

As a whole, this transfusing device can be formed in a size that can fitin the palm of a hand or be accommodated in a pocket. This is madepossible by the discharge mechanism of a simple structure shown withreference to the above embodiments. In this transfusing device, there isno need for the liquid medicine cartridge to be completely accommodatedin the case 150. As shown in FIG. 40, the main portion of the cartridgeis formed so as to protrude to the exterior of the case 150, whereby itis possible to further reduce the size of the case 150. In this case, aportable liquid medicine cartridge which is further reduced in size asneeded is attached, whereby it is possible for the size of the entiredevice to be further reduced. Such a reduction in the size of thetransfusing device is nowadays much required in medical facilities, andthe present invention provides a quite remarkable effect for medicaluse.

Industrial Applicability

As described above, in accordance with the present invention, atransfusing device, in particular, a transfusion pump, can be producedin a simpler form by reducing the number of parts, simplifying the partstructure, etc., so that it is possible to achieve a reduction inproduction cost. Further, it is possible to reduce the size and weightof the transfusing device. For example, it is possible to form thedevice as a portable transfusing device and to inject a minute amount ofliquid medicine into the body of the patient with high accuracy.

What is claimed is:
 1. A transfusing device comprising: a flexibleliquid supply tube; a support member supporting the liquid supply tubefrom one side; and a rotary drive member disposed adjacent to the liquidsupply tube on an opposite side of the support member and comprising: arotation shaft arranged substantially parallel to a direction in whichthe liquid supply tube extends, at least one pressing protrusion forpressurizing the liquid supply tube is integrally provided on an outerperipheral surface of the rotary drive member, and wherein the at leastone pressing protrusion is spirally arranged on the outer peripheralsurface of the rotary drive member; and a flexible sheet providedbetween the liquid supply tube and the outer peripheral surface of therotary drive member, wherein the flexible sheet is a partition formed ofthin material, and the partition comprises: a section having a pluralityof slits formed and arranged in a direction in which the liquid supplytube extends, the slits forming a plurality of strip-like lead members;and a base portion where no slits are formed, wherein in said baseportion said partition is fixed to a support plate.